Hand-held power tool

ABSTRACT

A hand-held power tool having a motor-driven impact mechanism and monostable operating button. A locking switch for the monostable operating button has a sliding direction, an actuating knob, a catch and a sliding block, wherein the actuating knob is able to be moved by the user in the sliding direction from a releasing position to a locking position. The catch is pivotable in a pivoting direction perpendicular to the switching direction between a first position and a second position. The catch is disengaged from the operating button  6  in the first position and the catch engages in the operating button in the second position, arresting the operating button in the pressed position. The catch has, on a side facing in the pivoting direction, a slotted-guide face that is inclined with respect to the sliding direction. The sliding block bears on the slotted-guide face.

FIELD OF THE INVENTION

The present invention relates to a chiseling hand-held power tool. Thehand-held power tool has a locking switch, which allows continuousoperation without the user having to keep an operating buttonpermanently pressed.

SUMMARY OF THE INVENTION

The hand-held power tool according to the invention has an impactmechanism, an electric motor for driving the impact mechanism, and amonostable operating button, which has a stable switching position and apressed switching position. A device controller switches off theelectric motor in response to the stable switching position andactivates the electric motor in response to the pressed switchingposition. A locking switch has a sliding direction, an actuating knob, acatch and a sliding block, wherein the actuating knob is able to bemoved by the user in the sliding direction from a releasing position toa locking position. The catch is pivotable in a pivoting directionperpendicular to the switching direction between a first position and asecond position. The catch is disengaged from the operating button inthe first position and the catch engages in the operating button in thesecond position, arresting the operating button in the pressed position.The catch has, on a side facing in the pivoting direction, aslotted-guide face that is inclined with respect to the slidingdirection. The sliding block bears on the slotted-guide face in thereleasing position.

In the releasing position, the sliding block disengages the catch fromthe operating button. The switching mechanism is robust with respect todust exposure and wear.

In one configuration, the catch has a spring, which applies a forcecounter to the pivoting direction to the catch. The spring acts in thesame direction as the sliding block.

The catch may have a side facing counter to the pivoting direction, onwhich side a further slotted-guide face that is inclined with respect tothe sliding direction is provided, and a finger is rigidly connected tothe actuating knob, wherein the finger bears on the furtherslotted-guide face.

The monostable operating button may have a restoring element, whichpreloads the operating button counter to the switching direction.

The monostable operating button may have a switching cap, which is ableto be gripped by a user and has a blocking face that interacts with thecatch.

The sliding block may be disengaged from the slotted-guide face in thesecond position of the catch.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description explains the invention with reference toexemplary embodiments and figures, in which:

FIG. 1 shows a hammer drill

FIG. 2 shows a rest position of the operating button

FIG. 3 shows a pressed position of the operating button

FIG. 4 shows a locked position of the operating button

FIG. 5 shows a detail view in the section plane V-V

FIG. 6 shows a detail view in the section plane VI-VI

FIG. 7 shows a detail view of the catch

DETAILED DESCRIPTION

Identical or functionally identical elements are indicated by the samereference signs in the figures, unless stated otherwise.

FIG. 1 schematically shows a hammer drill 1 as an example of a portablehand-held power tool. The illustrative hammer drill 1 has a tool holder2, into which a tool 3 can be inserted and locked. The tool 3 is forexample a drill bit, a chisel etc. The embodiment illustrated by way ofexample turns the tool holder 2 about a working axis 4 and at the sametime exerts periodically impacts on the tool along the working axis 4.The hand-held power tool 1 can have a mode selector switch 5, whichallows the user to selectively activate and deactivate the rotationalmovement and selectively activate and deactivate the percussiveoperation. The user can put the hand-held power tool 1 into operation bymeans of a monostable operating button 6.

The hand-held power tool 1 has a handle 7. The user can hold and guidethe hand-held power tool 1 during operation by way of the handle 7. Theoperating button 6 is preferably attached to the handle 7 in such a waythat the user can operate the operating button 6 using the hand holdingthe handle 7. The handle 7 can be decoupled from a machine housing 8 byway of damping elements.

The hand-held power tool 1 has a rotary drive 9, which is coupled to thetool holder 2. Among other things, the rotary drive 9 can have astep-down gear mechanism 10 and a slip clutch 11. An output shaft 12 ofthe rotary drive 9 is connected to the tool holder 2. The rotary drive 9is coupled to an electric motor 13. The user can switch the electricmotor 13 on and off by actuating the operating button 6, wherein theoperating button 6 accordingly controls a power supply to the electricmotor 13. In one embodiment, a rotational speed of the electric motor 13can be set by way of the operating button 6.

The hand-held power tool 1 has a pneumatic impact mechanism 14. Thepneumatic impact mechanism 14 has an exciter piston 15 and an impactpiston 16. The exciter piston 15 is rigidly coupled to the electricmotor 13. An eccentric wheel 17 and a connecting rod 18 convert therotational movement of the electric motor 13 into a movement intranslation on the working axis 4. The exciter piston 15 and the impactpiston 16 close off a pneumatic chamber 19 between one another. In theillustrated embodiment, radial closure of the pneumatic chamber 19 isprovided by a guide tube 20, which at the same time guides the exciterpiston 15 and the impact piston. In other embodiments, the impact pistoncan be of hollow design and the exciter piston 15 is guided in theimpact piston, or vice versa. The air enclosed in the pneumatic chamber19 is compressed and decompressed by the exciter piston 15. The changesin pressure couple the impact piston to the movement of the exciterpiston 15, and the pneumatic chamber 19 behaves in a similar manner to aspring, and is therefore also referred to as a pneumatic spring. Theimpact piston 16 can strike the tool 3 directly or strike the toolindirectly by way of an anvil 21.

The hand-held power tool 1 is switched on and off by the operatingbutton 6. The operating button 6 is arranged in the handle 7. Theoperating button 6 has a switching cap 22, which the user can grip. In arest position of the operating button 6, the switching cap 22 protrudesfrom the handle 7 counter to a switching direction 23 (FIG. 2). Theswitching cap 22 bears preferably against a stop 24 of the machinehousing 8. The user can press the switching cap 22 in the switchingdirection 23 into a pressed switching position (FIG. 3). In the process,the switching cap 22 can slide or pivot into the handle 7. The switchingcap 22 can, as illustrated in the illustrated example, be pivotableabout a bearing point or be guided in a linear manner. The switching cap22 is at a distance from the stop 24. A restoring element 25, forexample a helical spring, applies a force to the switching cap 22, saidforce acting counter to the switching direction 23. The restoringelement 25 is tensioned to a greater extent in the pressed switchingposition than in the rest position, with the result that the switchingcap 22 is stable only in the rest position. The switching cap 22 returnsto the rest position when the user releases the switching cap 22. Theswitching direction 23 is preferably antiparallel to the workingdirection 26 in which the tool 3 is directed.

The switching cap 22 is coupled to a switching mechanism 27 of theoperating button 6. The switching mechanism 27 deactivates the electricmotor 13 when the switching cap 22 is in the rest position. Theswitching mechanism 27 activates the electric motor 13 when theswitching cap 22 is in the pressed position. The switching mechanism 27may contain an electromechanical, optical, magnetic or other sensor fordetermining the position of the switching cap 22. In one embodiment, theswitching mechanism 27 can set a rotational speed or power consumptionof the electric motor 13 depending on positions that are pressed todifferent extents.

The hand-held power tool 1 has a locking switch 28. The locking switchhas a releasing position (FIG. 2; FIG. 3) and a locking position (FIG.4). The locking switch 28 has a pivotable catch 29, which engages in theswitching cap 22 in the locking position. The catch 29 arrests themovement of the switching cap 22 counter to the switching direction 23and therefore prevents the switching cap 22 from returning into the restposition. The operating button 6 remains in the pressed switchingposition. The electric motor 13 remains activated, even if the userreleases the switching cap 22.

The catch 29 interacts with the switching cap 22. The switching cap 22has a blocking face 30, on which the catch 29 can bear in the lockingposition. The blocking face 30 can be realized by the outer contour ofthe switching cap 22 or by an externally accessible rib or the like. Theblocking face 30 is preferably largely perpendicular to the switchingdirection 23. The blocking face 30 is directed counter to the switchingdirection 23 and toward the catch 29.

The catch 29 is pivotable in a pivoting direction 31 that isperpendicular to the switching direction 23. The catch 29 can be pivotedin the switching direction 23 between a first position, which isassociated with the releasing position, and a second position, which isassociated with the locking position. The catch 29 does not overlap theblocking face 30 in the releasing position. The overlap relates to theswitching direction 23, i.e. the overlap can be determined perpendicularto the switching direction 23 in projection onto a plane. The catch 29overlaps the blocking face 30 in the locking position. A tip 32 of thecatch 29 bears on the blocking face 30 in the switching direction 23. Ina similar manner to the gripping hand, the tip 32 exerts an opposingforce to the restoring element, with the result that the operatingbutton 6 remains pressed.

The position of the tip 32 along the switching direction 23 correspondsto the position of the blocking face 30 along the switching direction 23with the operating button 6 pressed. The tip 32 can project beyond theblocking face 30 in the switching direction 23 when the operating button6 is in the rest position. The locking switch 28 is inoperable when thehand-held power tool 1 is switched off.

The catch 29 is suspended for example on a resilient spring 33. Thespring 33 can be realized for example by a leaf spring, which isconnected at one end 34 to the machine housing 8. The spring 33 exerts aforce acting counter to the pivoting direction 31 on the catch 29. Thespring 33 can be relaxed, i.e. force-free, in the releasing position.The spring 33 is tensioned to a greater extent in the locking positionthan in the releasing position. The catch 29 has a tendency to moveautomatically from the locking position into the releasing position.

The locking switch 28 has an actuating knob 35, which is able to begripped by the user. The user can move the actuating knob 35 in asliding direction 36 between a first position and a second position. Thefirst position is associated with the releasing position of the lockingswitch 28 and the second position is associated with the lockingposition of the locking switch 28. The sliding direction 36 ispreferably parallel to the switching direction 23 of the operatingbutton 6. A slotted guide 37 couples the actuating knob 35 to the catch29.

The slotted guide 37 has a top side with an inclined slotted-guide face38. The top side points counter to the pivoting direction 31, forexample faces the actuating knob 35. The inclined slotted-guide face 38is inclined with respect to the switching direction 23. The inclinedslotted-guide face 38 is preferably inclined with respect to theswitching direction 23 in the releasing position and the lockingposition. The inclined slotted-guide face 38 descends in the pivotingdirection 31 along the switching direction 23. The actuating knob 35 hasa finger 39, which presses against the inclined slotted-guide face 38.The finger 39 moves the slotted guide 37 in the pivoting direction 31when the actuating knob 35 is moved into the locking position. The catch29 can press against the finger 39 in a manner preloaded by the spring33, both in the releasing position and in the locking position. Thecatch 29 returns from the locking position into the releasing positionby itself when the contact pressure exerted by the finger 39 decreasesas it moves along the inclined slotted-guide face 38.

The slotted guide 37 has a bottom side with an inclined slotted-guideface 40. The bottom side points in the pivoting direction 31, forexample faces away from the actuating knob 35. The inclinedslotted-guide face 40 is inclined with respect to the switchingdirection 23. The inclined slotted-guide face 40 ascends in the pivotingdirection 31 along the switching direction 23. The inclinedslotted-guide face 40 is preferably inclined with respect to theswitching direction 23 in the releasing position and the lockingposition. The actuating knob 35 has a sliding block 41, which, engagingbehind the slotted guide 37, can bear on the inclined slotted-guide face40. The sliding block 41 can lift the catch 29 out of the lockingposition in order to support the spring 33. The catch 29, the slottedguide 37 and the spring 33 are preferably in the form of a leaf spring.

FIG. 7 shows the slotted guide 37 and the catch 29 in a view onto thebottom side. The position of the locking switch 28 corresponds to FIG.4. In the locking position, the sliding block 41 is preferablydisengaged from the slotted guide 37. The engagement of the slidingblock 41 is realized for example by a narrower portion 42 of the slottedguide 37. The narrower portion 42, for example a cutout in the leafspring, adjoins the inclined slotted-guide face 40. The slotted-guideface 40 laterally overlaps the sliding block 41. In a correspondingmanner, the sliding block 41 can bear on the slotted-guide face 40 inthe releasing position, as illustrated in FIG. 3 and FIG. 5. Thenarrower portion 42 forms an opening, and when the sliding block 41 islocated therein, it is not in contact with the slotted-guide face 40.The arrangement and dimensions of the narrower portion 42 are chosensuch that the sliding block 41 does not overlap the portion 42 when thelocking switch 28 is in the locking position (cf. FIG. 6).

What is claimed is: 1-5. (canceled)
 6. A hand-held power toolcomprising: an impact mechanism; an electric motor for driving theimpact mechanism; a monostable operating button having a stableswitching position and a pressed switching position; a device controllerswitching off the electric motor in response to the stable switchingposition and activating the electric motor in response to the pressedswitching position; a locking switch having a sliding direction, andincluding an actuating knob, a catch and a sliding block, the actuatingknob movable by the user in the sliding direction from a releasingposition to a locking position; the catch being pivotable in a pivotingdirection perpendicular to the switching direction between a firstposition and a second position, the catch being disengaged from theoperating button in the first position and the catch engaging in theoperating button in the second position, arresting the operating buttonin the pressed position; the catch having, on a side facing in thepivoting direction, a slotted-guide face inclined with respect to thesliding direction; the sliding block being rigidly connected to theactuating knob and bearing on the slotted-guide face in the releasingposition.
 7. The hand-held power tool as recited in claim 6 wherein thecatch has a spring applying a force counter to the pivoting direction tothe catch.
 8. The hand-held power tool as recited in claim 6 wherein thecatch has a counter facing side facing counter to the pivotingdirection, a further slotted-guide face inclined with respect to thesliding direction being provided on the counter facing side, a fingerbeing rigidly connected to the actuating knob, the finger bearing on thefurther slotted-guide face.
 9. The hand-held power tool as recited inclaim 6 wherein the monostable operating button has a restoring elementpreloaing the operating button counter to the switching direction (23).10. The hand-held power tool as recited in claim 6 wherein themonostable operating button has a switching cap grippable by a user andhaving a blocking face interacting with the catch (29).
 11. Thehand-held power tool as recited in claim 6 wherein the sliding block isdisengaged from the slotted-guide face in the second position of thecatch.